1. Field of the Invention
The present invention is directed to a system for painting volumetric particle flow paths interactively and, more particularly, to allowing a user to interactively control the flow of volumetric particles or tubes around or on a geometry surface.
2. Description of the Related Art
Today there is a need to allow 3D graphics artists to paint realistic hair, grass, fire, smoke, water. fur, trees, etc. In such painting the flow of xe2x80x9celementsxe2x80x9d is important to the final image. Conventionally, a user has been allowed to set or place xe2x80x9cforcesxe2x80x9d in a 3D geometric scene and then run a batch simulation that generates particles. A display of the results is provided at the end of the simulation or at periodic intervals during the simulation. The control of this batch process is not interactive such that the user is not allowed to change the simulation as it is running. The user just gets what has been programmed. Because there is considerable delay between the setting of the forces and the production of the display, the production of images using these conventional techniques is not intuitive. Such conventional systems do allow the user to set the starting position of the simulation.
What is needed is a system that will allow a user to interactively xe2x80x9cpaintxe2x80x9d where particles are to start in association with a geometry and to xe2x80x9cpaintxe2x80x9d the forces on the particles or how the particles behave from the start to the finish of the simulation.
It is an object of the present invention to allow a user to paint particle flows onto and around geometries (for example, volumes) or onto mathematical constructs.
It is another object of the present invention to allow a user to paint the forces that act on particle flows as they are painted.
It is an object of the present invention to provide a system that interactively paints volumetric particles and interactively controls the flow of the particles.
It is an additional object of the present invention to display the particle interactively providing the user with immediate feedback.
It is also an object of the present invention to allow a user to paint the particles from any/multiple points of view.
It is a further object of the present invention to allow the user to control the flow (velocity, direction, etc.) of particles after they are produced via user inputs including the pointed paths, control points and control curves.
It is still another object of the present invention to reduce the need for memory during particle production by producing particles as they are needed and only while they are needed.
The above objects can be attained by a system that allows a user to paint volumetric particles or particle tubes using a brush stroke. The particles are emitted from an area around the stroke path as the stroke is being made, allowing the user to interact with the particle tubes being grown and change a direction of a stroke thereby affecting the final image. The system also allows the user to set or designate the stroke itself as a force which attracts or repels the particle tubes as they are generated, allowing the user to control the flow of the generated particles.
These together with other objects and advantages which will be subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.